New derivatives of benzylamide with anticonvulsant activity

Previously obtained picolinic acid benzylamide is a potent anticonvulsant with low neurotoxicity. In search for new effective anticonvulsants twelve new benzylamides (1-12) were synthesized and preliminary evaluated in the Anticonvulsant Screening Program (ASP) of Antiepileptic Drug Development Program (ADDP) of NIH. Two of them appeared the most promising: 1-cyclopentenecarboxylic acid benzylamide (1-Cpc-BZA) (9) showed MES ED50 = 85,36 mg/kg (PI = 2,49), scPTZ ED50 = 1,37 mg/kg (PI = 1,37), 6Hz-EST ED50 = 50,29 mg/kg and cyclopentanecarboxylic acid benzylamide (Cpc-BZA) (11) showed pilocarpine ED50 = 154.75 mg/kg and pilocarpine ED97 = 270.95 mg/kg.

Aryl aminopyrazole benzamides as oral non-steroidal selective glucocorticoid receptor agonists

Aryl aminopyrazole amides capped with N-alkylbenzamides 13-16 are selective glucocorticoid receptor agonists. 2,6-Disubstituted benzamides have prednisolone-like potency or better in vitro. Good oral exposure was demonstrated in the rat, with compounds with lower lipophilicity, for example N-hydroxyethyl benzamides (e.g., 16e).

Designing selective, high affinity ligands of 5-HT1D receptor by covalent dimerization of 5-HT1F ligands derived from 4-fluoro-N-[3-(1-methyl-4-piperidinyl)-1H-indol-5-yl]benzamide

We demonstrate here that covalent dimerization of 5-HT 1 ligands is an effective design strategy to modulate affinity and selectivity of 5-HT 1 ligands. This approach was applied to LY-334370, a selective agonist of 5-HT 1F receptor, to generate structurally well-defined divalent molecules. Radioligand binding assays to three cloned 5-HT 1 receptor subtypes (5-HT 1B, 5-HT 1D, 5-HT 1F) demonstrated that the affinity of a series of homologous dimers varied significantly upon exploration of three structural variables (linker length, attachment position, functionality). In particular, the series of C 3-to-C 3 linked dimers derived from a monomer ( 3) showed high binding affinity to 5-HT 1D (for example, K i approximately 0.3 nM for dimer 8) but did not bind to 5-HT 1F ( K i > 0.01 mM), providing >10000-fold subtype selectivity. Results from a functional assay (rabbit saphenous vein contraction) demonstrate that certain dimers are 5-HT 1 receptor agonists.

N-{[(6-Substituted-1,3-benzothiazole-2-yl)amino]carbonothioyl}-2/4-substituted benzamides: Synthesis and pharmacological evaluation

A series of 1,3-benzothiazol-2-yl benzamides (11-30) were prepared in satisfactory yield and evaluated for their anticonvulsant, neurotoxicity, CNS depressant study and other toxicity studies. All the synthesized compounds were in good agreement with elemental and spectral data. Majority of the compounds were active in MES and scPTZ screen and showed the decrease in the immobility time. None of the compounds had shown neurotoxicity or liver toxicity.

Derivatives of aryl-4-guanidinomethylbenzoate and N-aryl-4-guanidinomethylbenzamide as new antibacterial agents: synthesis and bioactivity

AIM

The aim of the present study was to design, synthesize, and evaluate novel antibacterial agents, derivatives of aryl-4-guanidinomethylbenzoate and N-aryl-4-guanidinomethylbenzamide.

METHODS

A total of 44 derivatives of aryl-4-guanidin-omethylbenzoate (series A) and N-aryl-4-guanidinomethylbenzamide (series B) were synthesized and their antibacterial activities were assessed in vitro against a variety of Gram-positive and Gram-negative bacteria by an agar dilution method.

RESULTS

Twelve compounds showed potent bactericidal effects against a panel of Gram-positive germs, including methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE), vancomycin-intermediate Staphylococcus aureus (VISA), and methicillin-resistant coagulase-negative staphylococci (MRCNS), with minimum inhibitory concentrations (MIC) ranging between 0.5 and 8 microg/mL, which were comparable to the MIC values of several marketed antibiotics. They exhibited weak or no activity on the Gram-negative bacteria tested. In addition, these compounds displayed high inhibitory activities towards oligopeptidase B of bacterial origin.

CONCLUSION

In comparison with the previously reported MIC values of several known antibiotics, the derivatives of aryl-4-guanidinomethylbenzoate and N-aryl-4-guanidinomethylbenzamide showed comparable in vitro bactericidal activities against VRE and VISA as linezolid. Their growth inhibitory effects on MRSA were similar to vancomycin, but were less potent than linezolid and vancomycin against MRCNS. This class of compounds may have the potential to be developed into narrow spectrum antibacterial agents against certain drug-resistant strains of bacteria.

Synthesis of functionalised aromatic oligamide rods

A current goal in synthetic chemistry is the design and synthesis of molecules that adopt well defined conformations-so called foldamers. In this manuscript we describe a modular approach for construction of rod shaped para-oligobenzamide molecules. Our approach permits regiospecific incorporation of side chains through a phenolic ether linkage on the scaffold; a feature that partly restricts the conformation of the rod through intramolecular hydrogen-bonding.

Synthesis of DL-fluorobenzenamides as anticonvulsants

DL-2-Hydroxy-2-phenyl butyramide (1, CAS 52839-87-9), DL-3-hydroxy-3-phenyl pentanamide (2, CAS 131802-69-2) and DL-4-hydroxy-4-phenyl hexanamide (3, CAS 67880-30-2) are anticonvulsants. Searching for more active compounds, some DL-fluorobenzenamides were prepared and tested: DL-2-hydroxy-2-(3'-trifluoromethylphenyl)butyramide (4), DL-2-Hydroxy-2-4'-trifluoromethylphenyl) butyramide (5, CAS 620950-10-9), DL-2-hydroxy-2-[3',5'-bis(trifluoromethyl)phenyl]butyramide (6, CAS 620950-09-6), DL-3-hydroxy-3-(3'-trifluoromethylphenyl) pentanamide (7), DL-3-hydroxy-3-(4'-trifluoromethylphenyl)pentanamide (8), and DL-3-hydroxy-3-[3',5'-bis(trifluoromethyl)phenyl]pentanamide (9, CAS 863976-07-2). Compounds 4-9 exhibited anticonvulsant activity in seizures induced by pentylenetetrazol in mice. Incorporation of trifluoromethyl groups in the phenyl ring of 1, 2 and 3 increased their potency. Compounds 4, 6 and 9 exhibited a similar anticonvulsant activity as the reference drug phenobarbital (CAS 50-06-6).

Synthesis of DL-hydroxybenzenamides as anticonvulsants

The anticonvulsant activity of some DL-hydroxybenzenamides is described. The following compounds from this series were prepared and tested: DL-2-hydroxy-2-(3'-bromophenyl)butyramide (4, CAS 620950-12-1), DL-2-hydroxy-2-(4'-bromophenyl)butyramide (5, CAS 620950-13-2), DL-2-hydroxy-2-(3'-nitrophenyl)butyramide (6, CAS 620950-14-3), DL-2-hydroxy-2-phenyl hexanamide (7, CAS 63002-05-1), DL-2-hydroxy-2-(3',4'-dichlorophenyl)hexanamide (8, CAS 863976-06-1), DL-3-hydroxy-3-(4'-bromophenyl)pentanamide (9, CAS 620950-16-5), DL-3-hydroxy-3-phenyl-heptanamide (10, CAS 863976-08-3) and DL-4-hydroxy-4-(4'-bromophenyl)hexanamide (11,CAS 620950-18-7). Compounds 4, 5, 9 and 11 exhibited significant activity in seizures induced by pentylenetetrazol. Incorporation of bromine in the phenyl ring increased their potency. Compounds 4, 5, 9 and 11 exhibited a similar anticonvulsant activity as the reference drug phenobarbital (CAS 50-06-6).

Design and synthesis of 4-[(s-triazin-2-ylamino)methyl]-N-(2-aminophenyl)-benzamides and their analogues as a novel class of histone deacetylase inhibitors

Inhibition of histone deacetylases (HDAC) is emerging as a new strategy in human cancer therapy. The synthesis and biological evaluation of a variety of 4-(heteroarylaminomethyl)-N-(2-aminophenyl)-benzamides is presented herein. From the different series bearing a six-membered heteroaromatic ring studied, the s-triazine series showed the best HDAC1 enzyme and in vitro anti-proliferative activities with IC(50) values below micromolar range. Some of these compounds can also significantly reduce tumor growth in human tumor xenograft models in mice.

Identification and synthesis of major metabolites of Vasopressin V2-receptor agonist WAY-151932, and antagonist, Lixivaptan®

Small molecule agonists and antagonists of the V(2)-vasopressin receptor have been discovered and have undergone clinical trials. In conjunction with these discovery programs, the synthesis and biological testing of various metabolites associated with these clinical targets were actively pursued. We now report the results of our synthetic efforts and the corresponding biological data generated for several of the metabolites of WAY-151932 and CL-347985 (Lixivaptan).

Discovering benzamide derivatives as glycogen phosphorylase inhibitors and their binding site at the enzyme

A series of novel benzamide derivatives was designed, synthesized, and their inhibitory activities against glycogen phosphorylase (GP) in the direction of glycogen synthesis by the release of phosphate from glucose-1-phosphate were evaluated. The structure-activity relationships (SAR) of these compounds are also presented. Within this series of compounds, 4m is the most potent GPa inhibitor (IC(50)=2.68 microM), which is nearly 100 times more potent than the initial compound 1. Analysis of mapping between pharmacophores of different binding sites and each compound demonstrated that these benzamide derivatives bind at the dimer interface of the rabbit muscle enzyme, and possible docking modes of compound 4m were explored by molecular docking simulation.

In vitro affinities of various halogenated benzamide derivatives as potential radioligands for non-invasive quantification of D2-like dopamine receptors

Benzamide derivatives as radiotracers have played an important role in diagnosing malfunction in dopaminergic neurotransmission. A variety of halogenated and two unsubstituted benzamide derivatives were synthesised and their in vitro affinities to dopaminergic, serotonergic and adrenergic receptors and their lipophilicities were determined. As references IBZM (3), raclopride (4) and FLB457 (5) were tested as well. The two iodinated compounds NAE (27) and NADE (28) displayed K(i) values of 0.68 and 14 nM for the D(2) receptor. The well-established radiotracers FP (1) and DMFP (2) showed affinities in the same range as did the brominated compounds NABrE (29) and NABrDE (30). The log D(7.4) values of 2.91 for NAE (27) and of 2.81 for NADE (28) are in the range of those found for IBZM (3), FP (1) and DMFP (2). These facts allow to expect good properties for the two iodinated compounds NAE (27) and NADE (28) regarding in vivo imaging with SPECT.

Pyrimidine benzamide-based thrombopoietin receptor agonists

A series of pyrimidine benzamide-based thrombopoietin receptor agonists is described. The lead molecule contains a 2-amino-5-unsubstituted thiazole, a group that has been associated with idiosyncratic toxicity. The potential for metabolic oxidation at C-5 of the thiazole, the likely source of toxic metabolites, was removed by substitution at C-5 or by replacing the thiazole with a thiadiazole. Potency in the series was improved by modifying the substituents on the pyrimidine and/or on the thiazole or thiadiazole pendant aryl ring. In vivo examination revealed that compounds from the series are not highly bioavailable. This is attributed to low solubility and poor permeability.

Vascular pharmacology of a novel cannabinoid-like compound, 3-(5-dimethylcarbamoyl-pent-1-enyl)-N-(2-hydroxy-1-methyl-ethyl)benzamide (VSN16) in the rat

BACKGROUND AND PURPOSE

A putative novel cannabinoid receptor mediates vasorelaxation to anandamide and abnormal-cannabidiol and is blocked by O-1918 and by high concentrations of rimonabant. This study investigates VSN16, a novel water-soluble agonist, as a vasorelaxant potentially acting at non-CB1, non-CB2 cannabinoid receptors in the vasculature.

EXPERIMENTAL APPROACH

VSN16 and some analogues were synthesized and assayed for vasodilator activity in the rat third generation mesenteric artery using wire myography. Also carried out with VSN16 were haemodynamic studies in conscious rats and binding studies to CB1 receptors of rat cerebellum.

KEY RESULTS

VSN16 relaxed mesenteric arteries in an endothelium-dependent manner. The vasorelaxation was antagonized by high concentrations of the classical cannabinoid antagonists, rimonabant and AM 251, as well as by O-1918, an antagonist at the abnormal-cannabidiol receptor but not at CB1 or CB2 receptors. It did not affect [3H]CP55,940 binding to CB1 receptors in rat cerebellum. The vasorelaxation was not pertussis toxin-sensitive but was reduced by inhibition of nitric oxide synthesis, Ca(2+)-sensitive K+ channels (KCa) and TRPV1 receptors. In conscious rats VSN16 transiently increased blood pressure and caused a longer-lasting increase in mesenteric vascular conductance. Structure-activity studies on vasorelaxation showed a stringent interaction with the target receptor.

CONCLUSIONS AND IMPLICATIONS

VSN16 is an agonist at a novel cannabinoid receptor of the vasculature. It acts on the endothelium to release nitric oxide and activate KCa and TRPV1. As it is water-soluble it might be useful in bringing about peripheral cannabinoid-like effects without accompanying central or severe cardiovascular responses.

Preparation and Optimization of a Series of 3-Carboxamido-5-phenacylaminopyrazole Bradykinin B1 Receptor Antagonists

The B1 receptor is an attractive target for the treatment of pain and inflammation. A series of 3-carboxamido-5-phenacylamino pyrazole B1 receptor antagonists are described that exhibit good potency against B1 and high selectivity over B2. Initially, N-unsubstituted pyrazoles were studied, but these compounds suffered from extensive glucuronidation in primates. This difficulty could be surmounted by the use of N-substituted pyrazoles. Optimization efforts culminated in compound 41, which has high receptor potency and metabolic stability.

Design, synthesis, and in vitro evaluation of carbamate derivatives of 2-benzoxazolyl- and 2-benzothiazolyl-(3-hydroxyphenyl)-methanones as novel fatty acid amide hydrolase inhibitors

Fatty acid amide hydrolase (FAAH) is an intracellular serine hydrolase, which catalyzes the hydrolysis of the endocannabinoid N-arachidonoylethanolamide to arachidonic acid and ethanolamine. FAAH also hydrolyzes another endocannabinoid, 2-arachidonoylglycerol (2-AG). However, 2-AG has been assumed to be hydrolyzed mainly by monoacylglycerol lipase (MAGL) or a MAGL-like enzyme. Inhibition of FAAH or MAGL activity might lead to beneficial effects in many physiological disorders such as pain, inflammation, and anxiety due to increased endocannabinoid-induced activation of cannabinoid receptors CB1 and CB2. In the present study, a total of 34 novel compounds were designed, synthesized, characterized, and tested against FAAH and MAGL-like enzyme activity. Altogether, 16 compounds were found to inhibit FAAH with half-maximal inhibition concentrations (IC50) between 28 and 380 nM. All the active compounds belong to the structural family of carbamates. Compounds 14 and 18 were found to be the most potent FAAH inhibitors, which may serve as lead structures for novel FAAH inhibitors.

A photoaffinity, non-steroidal, ecdysone agonist, bisacylhydrazine compound, RH-131039: characterization of binding and functional activity

In this paper we describe the synthesis, ligand-binding and functional activity characteristics of the photoaffinity, non-steroidal, ecdysone agonist, bisacylhydrazine compound, 3-benzoyl-benzoic acid N-tert-butyl-N'-(2-ethyl-3-methoxy-benzoyl)-hydrazide (RH-131039). Tritiated RH-131039 is the first non-steroidal photoaffinity compound that was shown to bind specifically to ecdysone receptors (EcRs) from insects belonging to the orders Diptera and Lepidoptera. The spruce budworm (Choristoneura fumiferana) ecdysone receptor (CfEcR) bound with high affinity (K(d)=2.23+/-0.27 nM) to this compound. When irradiated with UV light (lambda=350 nm) under equilibrium ligand-binding conditions, RH-131039 attached specifically and covalently to the CfEcR ligand-binding domain (LBD). RH-131039 also bound to cloned ecdysone receptor proteins from three dipteran insects, Drosophila melanogaster, Aedes aegypti and Chironomous tentans. This paper also describes and invokes caution in interpretation of ligand-binding results obtained using crude cellular extracts containing target receptors, as illustrated with the use of Drosophila Kc cells that have functional EcR and L57 cells (derivatives of Kc cells in which EcR-B isoforms have been knocked out by "parahomologous" recombination). Tritiated RH-131039 is a useful tool to dissect ligand-binding and functional differences for EcRs from different arthropod species.

New 2-arylpyrazolo[3,4-c]quinoline derivatives as potent and selective human A3 adenosine receptor antagonists. Synthesis, pharmacological evaluation, and ligand-receptor modeling studies

This paper reports the study of some 2-arylpyrazolo[3,4-c]quinolin-4-ones, 4-amines, and 4-amino-substituted derivatives designed as human A3 adenosine receptor (AR) antagonists. Most of the herein reported compounds showed a nanomolar affinity toward the hA3 receptor subtype and different degrees of selectivity that resulted to be strictly dependent on the presence and nature of the substituent on the 4-amino group. Bulky and lipophilic acyl groups, as well as the benzylcarbamoyl residue, afforded highly potent and selective hA3 receptor antagonists. The selected 4-diphenylacetylamino-2-phenylpyrazoloquinoline (25) and 4-dibenzoylamino-2-(4-methoxyphenyl)pyrazoloquinoline (36), tested in an in vitro rat model of cerebral ischemia, prevented the irreversible failure of synaptic activity induced by oxygen and glucose deprivation in the hippocampus. The observed structure-affinity relationships of this class of antagonists were also exhaustively rationalized using the recently published ligand-based homology modeling (LBHM) approach.

Synthesis and evaluation of novel radioiodinated benzamides for malignant melanoma

The imaging potential of a series of [123I]benzamides was studied in mice bearing B16F0 melanoma tumors. Compound [123I]25 exhibited tumor uptake >8 %ID/g at 1 h, while that of [123I]14d and [123I]25 reached a maximum of 9-12 %ID/g at 6 h. Standardized uptake values of [123I]14d were higher than 100 between 24 and 72 h after injection. In haloperidol treated animals, the tumor uptake of [123I]14d was not significantly different to controls, while significant reduction of [123I]25 uptake was observed, supporting that [123I]14d uptake relates to melanin interaction, whereas part of the mechanism of [123I]25 uptake is related to its sigma 1-receptor affinity. Benzamides 14d and 25, which display rapid and high tumor uptake, appear to be promising imaging agents for melanoma detection, while 14d, which displays a long lasting and high melanoma/nontarget ratio, is more suitable for evaluation as a potential radiotherapeutic.

Catalytic asymmetric phase-transfer Michael reaction and Mannich-type reaction of glycine Schiff bases with tartrate-derived diammonium salts

Catalytic asymmetric Michael and Mannich-type reactions of glycine Schiff bases with chiral two-center organocatalysts, tartrate-derived diammonium salts (TaDiASs), are described. On the basis of conformational studies, optimized TaDiASs with a 2,6-disubstituted cyclohexane spiroacetal were newly designed. These TaDiASs catalyzed the asymmetric Michael and Mannich-type reactions of glycine Schiff bases with higher enantioselectivity than previous catalysts. In the Mannich-type reaction, aromatic N-Boc-protected imines (Boc = tert-butoxycarbonyl) as well as enolizable alkyl imines were applicable. As a synthetic application of the catalytic asymmetric Mannich-type reaction with the optimized TaDiASs, we developed a catalytic asymmetric total synthesis of (+)-nemonapride, which is an antipsychotic agent.

Drug evaluation: MGCD-0103, a histone deacetylase inhibitor for the treatment of cancer

MethylGene Inc, in collaboration with Pharmion Corp, is developing the small-molecule, isoform-selective compound MGCD-0103 in North America for the potential treatment of cancer. MGCD-0103 is currently undergoing phase II clinical trials in patients with lymphoma, leukemia, myelodysplastic syndromes and solid tumors, including pancreatic carcinoma. Taiho Pharmaceutical Co Ltd is evaluating MGCD-0103 for oncological indications in South East Asia.

Synthesis, antimicrobial, and QSAR studies of substituted benzamides

A series of new substituted benzamides were synthesized and tested in vitro for their antibacterial activity against Gram-positive and Gram-negative bacteria and as well for antifungal activity. The compounds 8i and 9 showed better activity among the different benzamides synthesized. The structural characteristics governing antibacterial activities of substituted benzamides were studied using QSAR methodology. The results showed that the antimicrobial activity could be modeled using the topological descriptors, molecular connectivity indices (2chi(v) and 2chi) and Kiers shape index (kappaalpha1). The low residual activity and high cross-validated r2 values (r(cv)2) observed indicated the predictive ability of the developed QSAR models.

Novel non-steroidal inhibitors of human 11beta-hydroxysteroid dehydrogenase type 1

11beta-Hydroxysteroid dehydrogenase type 1 (11beta-HSD1) regulates glucocorticoid action at the pre-receptor stage by converting cortisone to cortisol. 11beta-HSD1 is selectively expressed in many tissues including the liver and adipose tissue where metabolic events are important. Metabolic syndrome relates to a number of metabolic abnormalities and currently has a prevalence of >20% in adult Americans. 11beta-HSD1 inhibitors are being investigated by many major pharmaceutical companies for type 2 diabetes and other abnormalities associated with metabolic syndrome. In this area of intense interest a number of structural types of 11beta-HSD1 inhibitor have been identified. It is important to have an array of structural types as the physicochemical properties of the compounds will determine tissue distribution, HPA effects, and ultimately clinical utility. Here we report the discovery and synthesis of three structurally different series of novel 11beta-HSD1 inhibitors that inhibit human 11beta-HSD1 in the low micromolar range. Docking studies with 1-3 into the crystal structure of human 11beta-HSD1 reveal how the molecules may interact with the enzyme and cofactor and give further scope for structure based drug design in the optimisation of these series.